This application is related to a U.S. Patent Application titled xe2x80x9cSystem to Pre-Qualify Copper Subscriber Loops for High Bandwidth Access Service Using Subscriber Voice Signalsxe2x80x9d and filed on the same day as the present application.
This invention relates to systems to qualify subscriber lines for high bandwidth access service and, in particular, to a system that provides a service provider with the ability to pre-qualify subscriber lines for high bandwidth access service where the service provider does not have direct metallic access to the subscriber line.
It is a problem in the field of high bandwidth access service for the service provider to determine the transmission characteristics of a subscriber line in an efficient and cost effective manner. The transmission characteristics of subscriber lines vary significantly due to a number of factors, including but not limited to: the length of the loop which comprises the subscriber line, the number and integrity of splices and connections made in the physical plant of the subscriber line, environmental soundness of the cable containing the conductors that are used to implement the subscriber line, the presence of load coils, and the like. Given the wide disparity in transmission characteristics of subscriber lines, it typically necessitates a craftsperson visit to the subscriber premises to execute tests on the subscriber line to ascertain the viability of this line for use in high bandwidth access service. The craftsperson runs transmission tests on the subscriber line by establishing a communication connection from the subscriber premises to a centrally located test facility. Various signals are then applied to this communication connection at the subscriber premises and compared with the signals received at the centrally located test facility. The resultant measured differences are indicative of the ability of the service provider to use this subscriber line for high bandwidth access service.
In contrast, service providers who manage the serving central office switch obtain a direct metallic connection to the selected subscriber line, exclusive of additional spans of communication circuitry, have the ability to directly measure the transmission characteristics of the selected subscriber line. The service provider can then collect data directly from the subscriber line which indicates the electrical characteristics of the subscriber line. This enables the service provider to pre-qualify subscriber loops for high bandwidth access service, without having to dispatch a craftsperson to the subscriber premises to execute tests on the subscriber line.
This disparity in access to the subscriber line facilities is reflected in a significantly higher cost to the service provider who does not have a direct metallic connection to the selected subscriber line, exclusive of additional spans of communication circuitry. This economic penalty represents a significant problem to these service providers in determining candidate subscribers for high bandwidth access service.
The above-described problems are solved and a technical advance achieved in the field by the system to pre-qualify copper subscriber loops for high bandwidth access service which determines electrical characteristics of a subscriber line served by a central office switch from a location remote from said subscriber line absent a direct metallic connection exclusively to said subscriber line. This is accomplished, where the subscriber line has subscriber equipment connected thereto at an end distant from said central office switch, by establishing a communication connection through the central office switch between the service provider and the subscriber equipment connected to said subscriber line. In response to the establishment of this communication connection, electrical signals, comprising subscriber or network generated signals, are applied to the subscriber line to enable the service provider to determine the electrical characteristics of the subscriber line by analyzing the received electrical signals. These generated signals can be Touch Tone signals generated by the subscriber telephone station set, dial pulses from a rotary dial subscriber telephone station set, tone signals generated by an auxiliary device connected to the subscriber line, computer generated modem tones, or tone signals reflected off the hybrid in the central office line card and/or subscriber telephone station set, which tone signals consist of tones generated by the service provider or call progress tones.
The involvement of the subscriber in the pre-qualification process significantly reduces the cost to service providers in determining candidate subscribers for high bandwidth access service. The subscriber generated signals can have a random or predetermined content. In particular, the subscriber may be asked to transmit a sequence of Touch Tone signals generated by the subscriber telephone station set, or a sequence of dial pulses from a rotary dial subscriber telephone station set, or tone signals generated by an auxiliary device connected to the subscriber line, or computer generated modem in order to obtain an output of sufficient duration and content to enable the system to pre-qualify copper subscriber loops for high bandwidth access service to execute subscriber line analysis routines. Alternatively, a subscriber line can be tested without the subscriber being involved in the test by the use of tone signals reflected off the hybrid in the central office line card and/or subscriber telephone station set, which tone signals consist of tones generated by the service provider or call progress tones.
While the addition of the spans of the communication connection through the serving central office and a customer loop to the service provider adds electrical characteristics to the end-to-end connection with the selected subscriber line, these additional characteristics can be factored in the final determination of the electrical characteristics of the subscriber line, since they are relatively constant over all communication connections to subscriber lines. Over time, a fairly accurate representation of these additional characteristics can be obtained and used to compensate for the presence of the additional spans in the communication connection. As a result, a relatively representative reading of the electrical characteristics of the subscriber line can be gained without the need to dispatch a craftsperson to the subscriber premises.